docs: more accurate docs about editon and style_edition options

Co-authored-by: Yacin Tmimi <[email protected]>

Author: karolzwolak

Configurations.md

@@ -539,7 +539,7 @@ Specifies which edition is used by the parser.
 
 The `edition` option determines the Rust language edition used for parsing the code. This is important for syntax compatibility but does not directly control formatting behavior (see [style_edition](#style_edition)).
 
-When running `cargo fmt`, the `edition` is automatically inferred from the `Cargo.toml` file. However, when running `rustfmt` directly, the `edition` must be explicitly set in the configuration file or via the command line.
+When running `cargo fmt`, the `edition` is automatically read from the `Cargo.toml` file. However, when running `rustfmt` directly the `edition` defaults to 2015 if not explicitly configured. For consistent parsing between rustfmt and `cargo fmt` you should configure the `edition`.
 For example in your `rustfmt.toml` file:
 
 ```toml
@@ -2808,10 +2808,10 @@ Controls the edition of the [Rust Style Guide] to use for formatting ([RFC 3338]
 
 This option is inferred from the [`edition`](#edition) if not specified.
 
-See [Rust Style Editions] for details on style editions.
-Starting with the 2024 edition, Rust introduced changes to default formatting. This can lead to inconsistencies between `rustfmt` and `cargo fmt` if the style edition is not explicitly configured. This is because `cargo fmt` automatically picks up the edition from `Cargo.toml`, while `rustfmt` defaults to the `2015` edition unless otherwise specified.
+See [Rust Style Editions] for details on formatting differences between style editions.
+rustfmt has a default style edition of `2015` while `cargo fmt` infers the style edition from the `edition` set in `Cargo.toml`. This can lead to inconsistencies between `rustfmt` and `cargo fmt` if the style edition is not explicitly configured.
 
-To ensure consistent formatting, it is recommended to specify the [`edition`](#edition) or `style_edition` in a `rustfmt.toml` configuration file. For example:
+To ensure consistent formatting, it is recommended to specify the `style_edition` in a `rustfmt.toml` configuration file. For example:
 
 ```toml
 style_edition = "2024"